Featured Scientist

Environmental Scientist Tom Greiner at the helm of CDFW research vessel Triakis.


CDFW Research Vessel Triakis on San Francisco Bay


Greiner holds a young leopard shark


Greiner on Humboldt Bay


Tom Greiner… just for the halibut

Thomas Greiner is an environmental scientist for the Aquaculture and Bays Management Project in CDFW’s Marine Region. He has more than 23 years experience with the department. Based out of the Santa Rosa office, his main duties include monitoring and management of the commercial herring fishery in San Francisco Bay and biological assessment of California’s estuaries.

Tom earned a double major in general Biology and Fine Arts from Eastern Michigan University. He came to CDFW in 1989 as a scientific aid. Afterwards he pursued a Master’s degree at Humboldt State University. After another stint as a scientific aide, Tom was hired as a Senior Laboratory Assistant for the CDFW’s San Francisco Bay Study and later promoted to Marine Biologist and Associate Biologist and is now an Environmental Scientist.

Who or what inspired you to become a scientist?

I have had an interest in nature, and animals in particular, since I was knee-high to a porcupine. My mother’s willingness to put up with all sorts of critters in the house certainly paved the way. Along the way several people tried to warn me that there are very few jobs in natural resources, but my stubbornness won out.

Can you give us an overview of the herring fishery and tell us why it’s important?

The primary commercial herring fishery in California occurs in San Francisco Bay. It is primarily a roe fishery with its product exported to Japan, where it is considered a delicacy and is a traditional holiday gift. There is also a smaller herring-eggs-on-kelp fishery and a fresh fish fishery for local consumption. In addition, there is a sport fishery for bait and food.

The San Francisco Bay herring fishery was once highly profitable, but a reduction in the price per ton paid to commercial fishers, due to competition from other fishing areas and diminishing demand in Japan, has led to reduced fishing effort.

What is a typical day like for you at work?

A typical day is spent in the office manipulating data and writing or editing documents, but work still takes me out into the field. In the summer, I occasionally help with fish rescues or sample the local estuaries by kayak using beach seines. Winter is my busy field season. I sample Pacific herring in San Francisco Bay aboard a research vessel by deploying a mid-water trawl. On a trawl day I typically get up long before sunrise and meet the crew, which consists of one boat operator (me or one of the other Herring Team biologists) and two winch operators. Once on the water, we look for cormorants, gulls, seals and sea lions to help us find schools of fish. After we have found a school, the vessel operator plans a strategy for the trawl which includes assessing potential hazards, determining tow direction (we tow with the current), and amount of line we need to let out to get the net down to the school of fish. We avoid trawling in rough seas or swift currents, but things can still get dicey – between vessel breakdowns, tangling up or ripping the net, and getting the net stuck in the substrate, trawling is often an adventure.

We collect data on age, length, weight and reproductive status from these samples. We use this data to assess condition of the San Francisco Bay Pacific herring spawning population. This information, along with a spawning biomass estimate made by another Herring Team member, is used to set the next season’s commercial fishing quota.

Managing the quota requires up to the hour information on herring fishing activity and landings along with coordinated, decisive action when calling for closure of the fishery to prevent over-exploitation of the herring resource. I coordinate fishery closures with the Herring Team, CDFW enforcement and the U.S. Coast Guard.

What is it about the work you do that you find most interesting or rewarding?

It is very rewarding working as part of a well-oiled (okay, occasionally squeaky) team to protect our natural resources. Precision teamwork is required both in the management of the commercial fishery and safely operating our sampling vessel.

What is the accomplishment you’re most proud of?

There isn’t one single accomplishment that I pride myself on above others, but instead it is my dependable, consistent, quality work. Through many years of study, I have developed a good reputation for reliable identification of estuarine fish and macroinvertebrate species. Continuous identification practice is important as I recently had a SNAFU concerning juvenile jacksmelt and topsmelt IDs – juvenile fish identification can be very tricky and the characteristics used to differentiate species in adult fish don’t always apply to the little guys.

If you had free reign and unlimited funding, what scientific project would you most like to do?

Restoring and protecting habitat and native wildlife and monitoring the recovery would be very rewarding. Healthy and varied habitat is often the key component in an ecosystem. One nice part is that this can be done on a small scale and some benefits may still be observed. Planting one tree can make a difference, especially in an urban area that lacks trees.

Are you a recreational angler (or hunter) yourself?

It has been quite a while, but I occasionally fish for food. I think that my main purpose in fishing is to make my friends feel good because they catch more fish than I do. It’s been much longer since I’ve hunted, but I also support the idea of hunting for food.

Do you have any advice for people considering careers in science or natural resources?

Get a degree in biological sciences, natural resources or related field. Meeting working biologists is very helpful and volunteering shows motivation. Be flexible in the job locations and positions that you are willing to accept. Very few people get permanent positions with CDFW right out of college. You need to have persistence, persistence, persistence, grit and patience. And learn to be frugal – you won’t make a lot of dough in this profession.

Top Photo: Tom Greiner, Arn Aarreberg and Ryan Watanabe identify and measure fish and invertebrates sampled by beach seine from Estero de San Antonio, a coastal lagoon in northern Marin County.

In 2013, Stuart Itoga became CDFW’s deer program coordinator, which means he is responsible for understanding, managing and conserving California’s deer populations. An avid outdoorsman, Stuart was born in Chicago and raised in San Jose. He holds a degree in Wildlife Management from Humboldt State University.

Stuart first joined the department in 1995 as a scientific aide at the Butte Valley Wildlife Area in Siskiyou County after holding fisheries and wildlife positions with the U.S. Forest Service. He is now a senior environmental scientist.

California is home to both mule and black-tailed deer, both resident and migratory herds that wander more than 70 percent of the state and number about 500,000 animals. At the dawn of the state’s 2017 deer hunting season (the general season opens Sept. 16 in many parts of the state), Stuart shared some personal background and his professional outlook on the state of deer management and deer hunting in California.

Who or what inspired your love of natural resources?

I always liked being outside, but hunting and fishing with friends really did it for me.

What do you like best about your job?

I get to work with so many great people. I work with scientists from other state agencies, and it’s enlightening to discuss different conservation approaches with other agency staff. But working on deer projects with our scientists is the best part. They really care about conserving deer and our other natural resources. It hasn’t all been good, but working together, we’ve been able to do some really good things over the past few years. I like the direction we’re headed.

Are you a deer hunter yourself?

I am – or I used to be, at least. When I started this job as the deer program coordinator, I thought it might help me figure out where the best spots were, but this job keeps me so busy I just haven’t made the time to get out deer hunting the past few years. It doesn’t look like I’ll get out there this season either.

Hunters often remark that California’s deer seasons start too early, and that overall hunter success would be much better if the seasons started later in the year, closer to the rut as is the case in many other states. What do you think?

We could start seasons later, which likely would result in greater levels of harvest that couldn’t be sustained over the long term. This would mean fewer tags for hunters. Having some early seasons allows us to provide tags to a greater number of hunters. Our hunter survey overwhelmingly indicated that hunters prized just the opportunity to get out and hunt deer. So we try to provide a balance of opportunity and high-quality hunts. You may not get the hunt you really want in a given year, but you will be able to get a tag to hunt somewhere.

There are very limited doe hunting opportunities in California compared to other states. Wouldn’t providing more doe hunts not only improve hunter success but also help improve the overall health of California’s herds by removing some older does no longer able to reproduce?

Doe hunts are typically conducted to reduce deer density and negative impacts to the herd and the habitat that result from too many deer. We are currently updating our baseline population data with new methods that allow us to estimate deer populations with a greater level of precision and accuracy. We are assessing where we might be seeing high-density impact at work. There are some areas where the densities are around 12 deer per square kilometer and others about four. The question we’re looking at now is how many deer are sustainable over the long term and what the appropriate levels of harvest – male and female – need to be.

Going back to our survey, 85 percent of hunters supported a doe hunt if data indicated it was warranted. However, having the supporting data and the support of hunters is only part of the equation. In California and other Western states, doe hunts are not widely supported by the non-hunting public, and 37 of California’s 58 counties can veto the department’s recommendations for antlerless hunts.

Mountain lions are another sore subject for many deer hunters. They often get blamed for suppressing California’s deer numbers. To what degree are mountain lions impacting California’s deer herds?

Mountain lions are deer predators as are bear, coyotes, bobcats and people. We’re updating our baseline deer population numbers, which will help us determine the level of significance associated with lion and other predation. Without a good starting number, it’s impossible to tell what impact lions – or other predators – are having on deer populations. In addition to our population study with deer, the department is assessing the mountain lion population, which will also provide valuable information on deer-lion interactions.

I personally think the number of people in the state may be the biggest stressor on deer populations. A population of almost 40 million people has quite an impact on the state’s natural resources.

What’s one message you’d like to share with deer hunters as they prepare to head out this season?

One thing I hear with some consistency is, “There are no bucks.” Our trail cameras and fecal DNA studies, however, are showing us there are.

We conducted a hunter survey a couple of years ago as part of an update of our California Deer Conservation and Management Plan. That survey, combined with the level of effort information we get from the harvest reports submitted by hunters, tell us the average California deer hunter spends about eight days in the field. That’s a good deal of time and effort. So I’m not saying it’s easy to get a buck, but hunters that are consistently successful put some effort into their hunt and also spend time scouting beforehand. If you can get out before your trip and pattern the deer, you’re going to increase your chances of being successful.

Good luck to all of our deer hunters this year! If you’re successful, send me a photo at stuart.itoga@wildlife.ca.gov. (Don’t forget to tag it first!)

Sara Holm is an environmental scientist with the Wildlife Management Program in CDFW’s North Central Region. Based in Colfax, she is the unit wildlife biologist for Placer and Nevada counties. Her work includes a multi-agency wildlife-crossing project, collared mule deer studies, coordinating the region’s upland game bird hunts, land acquisition and management and many resource assessment projects and surveys. She works primarily with deer, bear, dove, pheasant and turkey but dabbles with lions, elk and bighorn sheep. Critical aspects of her work include responding to wildlife conflicts and providing technical expertise to hunters and the public.

Sara earned a Bachelor of Science degree in Wildlife Management from Humboldt State University in 1999 and started her career two days later as a scientific aide with CDFW. She has worked in the North Central Region for 17 years. She also recently became a hunter education instructor.

What led you into a career as a wildlife biologist?

I credit my family for introducing me to wildlife. The first vacations I can remember were camping, fishing and visiting national parks like Yosemite, Glacier and Yellowstone. There is nothing as exciting as a bear jam (a traffic jam caused by tourists stopping their cars on the side of the road to view bears) in Yellowstone, or that quick flash of a trout taking your fly.

When I was young, I knew I wanted to work outside but all I could envision was being a park ranger. I took a forestry class in junior college but realized that was not quite right for me. My biology professor told me about Humboldt State University and CDFW, so I volunteered with CDFW’s Wildlife Investigations Lab. That is when I realized I could be a wildlife biologist and that I wanted to work for CDFW. It was all fascinating work, whether I was pulling a bear tooth at the front counter, feeding a lion in the pens or responding to a deer stuck in a fence.

I am inspired by the resources and by the chance to make a difference with science. It always made me proud to know I worked for the wildlife as well as the hunters (and anglers). When I complete a great project that I know will help wildlife, or validate a deer tag and talk to another happy outdoor enthusiast, I know that I am in the right place.

What is a typical day like for you at work?

One of the things I like best about my job is that it is never typical! On an office day I may start out answering nuisance wildlife calls, doing paperwork, checking on our collared deer locations or catching up on data entry -- but I could get a call that takes me into the field, to help an injured animal or check damage caused by a bear or lion. When I know I will be in the field the day usually starts early and could take me anywhere in my unit, or throughout the region to help on a colleague’s project.

The work can be hard if you are putting in 14-hour days trying to collar deer and you do not see a single animal, or you come out of the field to 20 messages on your phone, but I would do most of it for free because it is so fun. I have collared tons of deer, put bear cubs out in dens, flown many helicopter surveys, captured bighorn sheep and had many great adventures, but all of the work I do is made better by my fellow biologists. They are a second family to me and we have fun together, whether we are at a meeting or around the campfire. I think everyone should love their job but I am lucky to love the people I work with.

What is your favorite species to interact with or study?

I have a hard time choosing and I am always looking to work with something new. I love seeing fuzzy quail babies in the summer and flushing blue grouse out in the woods but I am more of a mammal person. I mostly work with mule deer and they are more fascinating than they look. Ground darting is anything but routine, as each captured animal is different. It is so exciting to get collar data back and see how and where they moved.

What aspect of working in the Sierra Nevada foothills is unique?

The foothills are interesting, especially considering my unit covers the foothills all the way over the crest of the Sierra to the Tahoe Basin (the elephant in this room is actually a bear!). The most complex part of this area is that there are many people living in urban environments that are actually in rural settings. Communities and pets, including livestock, actually create habitat in areas that are not ideal for wildlife. A pond in the middle of a small town attracts too many geese or maybe invites beavers that then flood roads. Rose bushes attract deer, which draw in lions. People want to raise chickens and then bears walk past homes and across busy roads to eat them. Sometimes I evaluate human-wildlife conflict in a busy city like Auburn, and other times I have to drive an hour out a dirt road for a similar issue.

What is the most rewarding project that you’ve worked on for CDFW?

I am the most proud of my work with the Highway 89 Stewardship Team. Our inter-agency team has built three wildlife crossings with fencing and wildlife jump-outs (which allow animals an exit point if they are within a fence) that are allowing animals to get across the road safely, connecting their habitat and making it safer for drivers. We have mentored other teams and run a successful program for students to teach others about the problems roads cause and the available solutions. These crossings will be in place long after I am gone, so it is a legacy that I can leave on the landscape.

If you had free reign and unlimited funding, what scientific project would you most like to do?

I believe we are currently doing projects that are good science and important for our agency but we could always do them better. I completed a project to evaluate the feasibility of reintroducing desert bighorn sheep to the North Central Region. With enough time, money, and legwork we may be able to clear out the livestock and make it happen. I would love to release some collared animals back in the Truckee River Canyon, spend my days monitoring them and witness their successful return to the area.

Is there a preconception about scientists you would like to dispel?

I guess I would dispel any lasting notions that science is only for men. I work with several other “lady bios” and I am proud of how we operate and the skills that we have. Sometimes when you are talking to the public, they will misconceive what you know or can do just because you are a female. After providing technical assistance I’ve been asked how long I’ve done this job as if to validate my credibility, or I’ve had questions automatically directed at male counterparts even though it’s my area and I’m the one who can answer the question.

Any advice for people considering careers in science or natural resources?

Be persistent and open to opportunity where it is available. We tend not to leave our jobs, so you may have to put in time and wait for something permanent to open up, but you can find a natural resource job in unexpected places like airports or land trusts. Volunteering and meeting people are how I got in. I would advise people to work hard for what they want because this is the best job!